I stuck an SSD in my PS3. The gains are marginal, especially given it's a 240gb Kingston and not a 1tb Samsung one, but there is a small boost. Tested on Castlevania: Harmony of Despair.
Honestly it seems like a pretty good deal to me. Having one means you either own a PS3 and Ps2 in one or a PS3 and ps1 in one.
Sure, the disc based media is slow but has it ever been fast?
Don't get me wrong the original retail price of $599 USD was ridiculous. Actually more expensive than a PS5 currently. That, along with disabling the 8th core and the wonderful CELL ARCHITECTURE, definitely paints a picture of the PS3's flaws.
With that being said you've got some pretty cool exclusives. The Ninja Gaiden Sigma remasters, Asura's Wrath, 3D Dot Game Heroes, that one japan exclusive .hack//versus fighting game, God of War, Metal Gear... Ratchet and clank!
The console has its issues but overall if you're looking to play some great games the PS3 has some great choices. The backwards compatibility helps the device keep up even with some other flaws. Given the fact the PS4 can't play Ps3 games WELL, (and assuming you're against emulation), I think it's a worthwhile purchase, but to each their own.